The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Electrochemical cells, such as fuel cells, generate electrical power through the electrochemical reaction of a reactant and an oxidant. An exemplary fuel cell has a membrane electrode assembly (MEA) with catalytic electrodes and a proton exchange membrane (PEM) sandwiched between the electrodes. In preferred PEM type fuel cells, hydrogen is supplied as a reductant (or fuel) to an anode, and oxygen is supplied as an oxidant to a cathode. PEM fuel cells reduce oxygen at the cathodes and generate an energy supply for various applications, including vehicles.
Bipolar PEM fuel cells comprise a plurality of MEAs stacked together in electrical series. Typically, each MEA is sandwiched between a pair of electrically conductive contact elements, preferably bipolar plates that serve as current collectors for the anode and cathode. Generally, the bipolar plates comprise two independent plates, preferably having a void between them for coolant flow. The bipolar plates may also contain appropriate channels and openings thereon for distributing the fuel cell's gaseous reactants (i.e., H2 and O2/air) over the surfaces of the respective anode and cathode.
Polymer composite materials are desirable for bipolar plates, as they are chemically inert and generally do not comprise iron-containing contaminates. Presently, bipolar plates are made from thermosetting polymers in a compression molding process. The compression molding process is slow and expensive, with substantial tooling costs. Further, thermosetting polymers cannot be joined by ultrasonic or laser welding, requiring costly thermosetting adhesives to be used to join halves of a bipolar plate. Thus, there remains a need for a method of manufacturing bipolar plates at a high volume production that avoids problems associated with known processes and improves bipolar plate performance, efficiency, and lifespan in the fuel cell.